This is an original patent application of provisional application Ser. No. 60/064,818 filed Nov. 7, 1997.
This invention relates generally to disc drive data storage devices and more particularly, it relates to a head disc drive assembly damper configuration for use with a disc storage device designed with shock mounts so as to compensate for reduced rigidity.
As is generally well-known in the art, disc drive data storage devices are used in modern microcomputers such as personal computers and the like. One type of such devices known in the industry is referred to as a "Winchester" disc drive in which one or more rotatably driven memory storage discs are mounted within a substantially sealed disc drive assembly along with a corresponding electromagnetic transducer carried in a slider body. The slider body has a self-acting hydrodynamic air bearing which "flies" the transducer a very small distance above the surface of the disc. In this fashion, digital data is recorded on (writing) and retrieved from (reading) from a thin layer of magnetizable material on the surface of the spinning disc.
The slide/transducer subassembly is typically referred to as a "head" and a single head is generally associated with each disc surface. The heads are controlled by electronic circuitry for selectively moving them to any one of a plurality of circular, concentric data tracks on the disc surface by an actuator device. Further, the head disc assembly is mounted onto a rigid frame or chassis for connection to an external apparatus such as a personal computer. In addition, in order to meet high non-operating shock requirements, such as greater than 200 Gs (2 ms pulse) shock absorbers or shock mounts are suitably affixed to the head disc assembly for supporting the same from the rigid chassis. Such prior art shock mounts, as shown in FIG. 1, are used to isolate the disc and corresponding heads from undesired shocks and vibrations in the vertical or Z-direction which might cause tracking errors during the course of reading and writing data.
It is also generally known that past disc drives of this above-discussed type were manufactured in the 51/4 inch form factor where the data tracks are distributed on the surfaces of the disc at a radial track density of 300-400 tracks per inch (TPI) and the heads were located approximately 12-14 microinch above the disc surfaces. In view of recent trends for smaller form factors and increased data storage capacity, there have been produced disc drives with track density in the range between 1800 and 10,000 TPI and head dimensions between 1.0-4.0 microinch above the disc surfaces. Currently, disc drives are being manufactured in the 31/2 inch and smaller form factors. Thus, due to the ever increasing trends for higher number of tracks per inch, the disc drives being manufactured can no longer meet the operating vibration requirement in the X-Y plane with the existing shock mounts.
Therefore, it would be desirable to provide a head disc drive assembly damper for use with a disc storage device designed with shock mounts so as to improve the operating vibration in the X-Y plane. Further, it would be expedient to improve the servo tracking ability during low frequency operating vibration but yet maintain the non-op shock absorption characteristics of the shock mounts.